Van Schaick turned to his papers.
"In the last century," he said, "a curious thing happened to an English explorer, Ney Elias. I quote from his book. An old man called on me at Kwei-hwa-ching, at the eastern end of the Thian Shan Mountains, who said he was neither Chinaman, Mongol, nor Mohammedan, and lived on ground especially allotted by the emperor, and where there now exist several families of the same origin. He said that he had been a prince. At Kwei-hwa-ching I was very closely spied on and warned against asking too many questions."
Van Schaick peered over his spectacles at Gray.
"The Thian Shan Mountains are just north of this blind spot in the Gobi Desert where we think the Wusun are."
The historian broke in eagerly.
"Another clew—a generation ago the Russian explorer, Colonel Przewalski, tried to enter this blind spot from the south, and was fought off with much bloodshed by one of the guardian tribes."
Gray laughed frankly.
"I admit I'm surprised, gentlemen. Until now I thought you were playing some kind of a joke on me."
Van Schaick's thin face flushed, but he spoke calmly.
"It is only fair, sir, that you should have proof you are not being sent after a will-o'-the-wisp. A few days ago I talked with a missionary who had been invalided home from China. His name is Jacob Brent. He has been for twenty years head of the college of Chengtu, in Western China. He heard rumors of a captive tribe in the heart of the Gobi. And he saw one of the Wusun."